What Is Integration Testing Explain It with Example?

When individual software modules are merged and tested as a group than it is
known as integration testing. Integration testing is sets between
Unit Testing and System Testing.

Integration Testing Example

For example you have to test the keyboard of a
computer than it is a unit testing but when you have to combine the keyboard and
mouse of a computer together to see its working or not than it is the integration testing. So it is prerequisite
that for performing integration testing
a system must be unit tested before.

Black-box test case design tactics are the most
typical during integration, although limited amount of testing of white box may
be used to ensure description of major control paths.

What is Integration Testing?

Integration testing is executed to establish whether the components interact with each other consort to the specification or not.Integration testing in large refers to joining all the components resulting in the complete system. It is further performed by the developer or the software Tester or by both. Example- checking that a Payroll system interacts as required with the Human Resource system.

Integration testingis always sub-divided as follows:

Types of Integration Testing

1) Top-Down Integration Testing: Top Down Integration as the term suggests, starts always at the top of the program hierarchy and
travels towards its branches. This can be done in either depth-first or breadth-first.

2) Bottom-Up Integration Testing: Bottom –Up
integration as it name implies starts at the lowest level in the program structure.

Some Techniques
of integration testing: Techniques
of integration testingcan
be given below

1) Top-down testing
approach

2) Bottom-up testing
approach

3) Big-Bang testing
approach

4) Sandwiched testing
approach

Conclusion: At last we
conclude that Integration testing
focuses on testing multiple modules working together.

Integration testing (sometimes called the Integration and Testing, abbreviated as I and T) is one of the extensive exercises of the software testing in which particular software modules are merged and tested as a group.

If we have 4 apps, in one its 2, in 2nd its 3, in 3rd app, its 2*3 and in 4th, its 6....What testing it would be? Integration testing or System testing, please explain. I faced this question in interview and was dumbstruck.

The goal of integration testing is to make sure a system consisting of a number of components will function according to specifications when all the components are put together. If that is the case, why spend time testing interfaces between interacting modules? Why not just put them all together and test the system as a whole? can anyone Give arguments both for and against with examples.